1. Field of the Invention
The present invention relates to a chemical amplification resist composition for use in manufacturing processes of semiconductor devices, such as lithographic printing plate and IC, manufacture of circuit substrates of liquid crystals, thermal heads and the like, and other photo-fabrication processes, and also the invention relates to a pattern-forming process using the same. In particular, the invention relates to a chemical amplification resist composition that functions by high energy radiation such as far ultraviolet rays (including excimer lasers), electron beams, X-rays or radiant rays, suitable for the manufacture of a semiconductor integrated circuit, and the invention also relates to a pattern-forming process using the same.
2. Background Art
In the manufacturing process of semiconductor devices such as IC and LSI, fine processing by lithography using photo-resist compositions has been conventionally performed. In recent years, with the increment of integration of integrated circuits, ultrafine pattern formation of the level of a sub-micron and quarter-micron has come to be required. Under such a circumstance, the exposure wavelengths show a tendency to be shortening, such as from g-ray to i-ray, further to KrF excimer laser ray. Nowadays, lithography using excimer laser rays is an important processing technique in this field, and chemical amplification resists are adopted as the resists suitable for such an excimer laser lithography process.
Chemical amplification resist compositions are materials that form a pattern on a substrate by generating an acid upon irradiation with radiation such as far ultraviolet rays on the exposed area, and making difference in solubility in a developing solution of the exposed area and unexposed area with the actinic radiation. Chemical amplification resist compositions are advantageous in that they have high sensitivity and high resolution, and they can form an image with a compound capable of generating an acid (hereinafter referred to as “a photo-acid generator”) by irradiation with a small quantity of radiation.
The above chemical amplification resist compositions can be classified broadly into (a) s three-component system comprising an alkali-soluble resin, a photo-acid generator, and a compound having an acid-decomposable group that inhibits dissolution of an alkali-soluble resin, (b) a two-component system comprising a resin having a group decomposable by the reaction with an acid and becoming alkali-soluble, and a photo-acid generator, and (c) a hybrid system comprising a resin having a group decomposable by the reaction with an acid and becoming alkali-soluble, a low molecular weight dissolution-inhibiting compound having an acid-decomposable group, and a photo-acid generator. In every positive chemical amplification resist of these two-component system, three-component system and hybrid system, a resist pattern is formed by the development after heat treatment via an acid generated from photo-acid generator upon exposure.
In lithography using chemical amplification resists, photo-resists are generally required to be excellent in various characteristics, e.g., sensitivity, resolution, profile, a coating property, heat resistance, dry etching resistance, adhesion, substrate dependency, stability resisting to environmental fluctuations (e.g., dimensional stability of a resist due to the fluctuation of lying time), and focal depth (e.g., a pattern-forming property to focal deviation at the time of irradiation with radiation), and various contrivances of the improvement of performances by means of additives are disclosed.
For example, the addition of an aromatic hydroxyl compound to a chemical amplification resist composition for the increment of sensitivity is disclosed in patent literature 1 (JP-A-4-217251 (the term “JP-A” as used herein refers to an “unexamined published Japanese patent application”).
A trial of the addition of a compound having a fluorine atom in the molecule to a chemical amplification resist composition for the purpose of lessening the problem of development defect is disclosed in patent literature 2 (JP-A-2003-156845).
The addition of a specific alcohol to a chemical amplification resist composition for the improvement of the reproducibility and stability of a pattern is disclosed in patent literature 3 (JP-A-9-185158).
Further, the addition of a chain-like compound having three or more hydroxyl groups or substituted hydroxyl groups to a chemical amplification resist composition for the improvement of line edge roughness to thereby prevent the collapse of a pattern is disclosed in patent literature 4 (JP-A-2003-270791).
However, even with these techniques, it is difficult to obtain a chemical amplification resist composition that satisfies at the same time the three points of capable of forming a good pattern profile, being hardly accompanied by development defect and capable of preventing pattern collapse.